[time-nuts] Some results of PRS10 and Trimble Resolution T

[SAIDJACK at aol.com]

Hello Ulrich, Erik,
 
attached are two plots of high-quality phase-noise measurements of my  PRS10 
Rubidium and of our new low-cost GPSDO prototype in comparison  as measured on 
the new TSC5120A.
 
My PRS10 measurement actually shows less spurs (only a couple  are visible) 
on it than the SRS-provided graph shown on the SRS  website. Did they use old 
equipment to measure it??
 
It's nice to see that our GPSDO has lower phase noise than the SRS unit  
above 1KHz. 
 
I still don't really understand why the PRS10 Rubidium has such a bad  2s 
Allan Deviation with a 7-hour 1PPS filter time, also  considering this kind of 
nice low Phase noise. 
 
Thinking about this further I think it may be an inherent problem in the  
PRS10 independent of GPS lock: take a look at their ADEV plot on the  SRS 
website, it can be seen from the plot that there is no  difference in ADEV locked or 
unlocked to GPS below 1000s measurement  intervalls:
 
_http://www.thinksrs.com/products/PRS10.htm_ 
(http://www.thinksrs.com/products/PRS10.htm) 
 
>From their SRS ADEV plot, it can also be inferred by interpolation  that the 
1s ADEV is above 1E-011 (also their spec), that's probably why they  only 
start the plot at 10s intervalls...
 
Sorry to post to the entire group, its a tiny file and I think many of  you 
have PRS10's, hope that's ok...
 
bye,
Said
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